T61p free PCI express slot... ?

[Yacek]

After having a quick loot at manual, I understand that there is one free pci slot.. unless TurboMemory card is installed, right?
I'm just thinking about adding WWAN (GSM) sierra card to free one USB slot

I found the place around battery compund where SIM card should be... but in my thinkpad it's rubbered with something. So my question is: If I install sierra card instead of turbo memory card, is to so easy to remove rubber thing from SIM slot? Or it;s not so easy and additional modification is needed? Any experience with such modding ?
Thanks in advance
Yacek